Dehairing process



March 5, 1957 B. L. THOMAS 53 I 6 a 11 l a, I" g 0 INVENTR. 1 6 44/ C flag I ATTORNE 1.

United States Patent O DEHAIRING PROCESS Brice L. Thomas, Western Springs, Ill.

Application February 25, 1955, Serial No. 490,613

6 Claims. (Cl. 17-45) This invention relates to an improved process for the removal of hair and other keratinous material from an animal carcass. In one of its aspects this invention relates to a process for loosening hair roots from the follicles on animal carcasses. In another of its aspects this invention relates to an apparatus for loosening the filamentary keartinous materials on animal carcasses.

In the meat packing industry it is the practice in the processing of pork to completely dehair the hog carcass after killing and before evisceration. The dehairing operation is an extremely significant one, having a direct effect on the grading of the meat on inspection, the cost of the operation and the profit to be made on the animal. The conventional method of dehairing a hog carcass involves first scalding by dunking in a tank of hot water to loosen the hair and scurf and then putting the carcass through a mechanical dehairing machine where it is subjected to a beating action of scrapers. In the scalding of the carcass, the temperature of the water and the time and manner of dunking must be carefully controlled not only for the purpose of getting a uniform scald but to avoid overor under-scalding. Overscalding is usually manifested by emulsified backs and white blotches on the skin of the carcass. This is caused either by the water being too hot in the tub or the dehairing machine, or by the carcasses remaining in' the water longer than necessary. The white blotches on the skin are excessively gluey, and generally result in torn skins due to the beater action of the scraper blades. Badly over-scalded hogs have to be skinned and trimmed, causing money losses through decreased yields and increased direct labor costs. Further, only the skins of properly scalded hogs can beused by tanners. Underscalding is usually manifested by excessive hair and scurf n-the hog carcasses coming out of the dehairing machine, making singeing and shaving difficult and expensive. The presence of any scurf on a carcass indicates either too rapid scalding, or low or irregular temperatures of the water in the dehairing machine or scalding tub. Under-scalded raw hogs, like over-scalded hogs, cause excessive production line stoppages, added cleaning labor, carcass mutilations from trimming, and lowered grading. Without thorough scalding carcasses cannot be satisfactorily cleaned at a uniform cost perflhundred weight.

In the dehairing operation, it is not only necessary to remove the hair stems, but also desirable to eliminate thehair roots. The failure to eliminate the hair roots from a carcass is usually due to under-scalding which necessitates shaving and singeing. While the shaving a nd'singeing may remove the hair stems, the roots are still left in the hide and a carcass having a sizable quantity of hair roots is non-uniform in its color and ap pearance. Therefore, the animal carcass is graded'lower and'the price obtainable for the heat therefrom is less. Further, the mere necessity for shaving and singeing increases the processing cost and'reduce's the prices which 'ice the hide will bring when sold to tanners for processing into leather.

According to my invention, many of the aforementioned shortcomings of present dehairing processes can be substantially overcome by treating the carcass in a particular manner whereby the hair roots are loosened without dunking the carcass in a tank of water. By my method the entire carcass is subjected to uniform conditions of pressure, temperature and humidity to bring about a loosening of the hair follicles to a degree heretofore nnobtainable. By virtue of this improvement in the loosening of the hair follicles, it is possible to remove the hair from the carcass without subjecting it to the beating action of blades in a mechanical dehairing machine. That is, after pretreatment the hair stems with the roots attached can be removed by the action of jet streams, such as water, air and/or steam. Thus, the necessity for shaving and singeing can be eliminated along with the disadvantages attendant therewith as hereinbefore described. 7

It is, therefore, an object of this invention to provide an improved process for the removal of filamentary keratinous material from an animal carcass.

It is another object of this invention to provide a. process for loosening hair roots from the follicles on ani mal carcasses.

Still another object of this invention is to provide an apparatus for loosening the filamentary keratinous ma-;

terials on animal carcasses.

Further and additional objects of this invention will drical device specially fitted to accommodate animal carcasses rotates about a horizontally disposed axis; a

Figure 2 is a cross section taken through the cylindrical device along the line 22 of Figure 1;

Figure 3 is a longitudinal section of another embodiment of my apparatus wherein the cylindrical device rotates about a vertically disposed axis;

Figure 4 is a plan view, partly in section, of this sameembodiment; V a

Figure 5 is a longitudinal section through the chamber of an apparatus in which the hog carcass is dehaired by the action of jets; and

Figure 6 is a top sectional plan of the same apparatus.

In accordance with my invention, the animal carcass is subjected, for a period of atleast 5 seconds and not more than 6 or 7 minutes, to a temperature in the range of 125 to 500 F. and a total pressure of from 20 .to lbs. per square inch absolute, sai-d absolute pressure being supplied either in part or in toto by water vapor. The pressure of the water vapor can be as low as 4 and as high as about 100 pounds per square inch absolute. However, when hot air is the principal pressurizing medium, it should be completely saturated with water vapor' and it is preferred to have a fine mist of water present during the treatment. It willbe understood that the higher temperatures are employed for the shorter periods of time and vice versa. It will also be appreciated that the conditions to which the carcass is subjected willvar'y depending upon the kind and size of the animal and also the season during which it is being processed. At certain times of the year the hair is thicker on the carcass 30 lbs. per square inch absolute havinga partial water vapor pressure of aboutli lbs. per square inch absolute.

By subjecting the carcass to the aforementioned conditions, it is. believed that the air and/or moisture at the proper. temperature and under pressure-permeatethefol licles on the carcass and dissolve the substance binding the hair root. Thus, when the hair stem is subsequently subjected; tosa mechanical action; theroot comes out along with the stem. By virtue of this loosening of the-hair-roots it: is possible to remove them v along with the' stemsvmcltely by subjecting the carcass to the actionof high pressure jet streams, suchas water; air and/or steam. One of the practical limitationswithrespect to. the use ofi mechanical dehairing machines is that itis extremely diiiicult, it not impossible, to-have the entire-- surface-of thecarcass subjected tothebeating action of the scraper bl'ades. Further, the beating action tends tobreak the hair stemshaving roots still firmly embedd'edin the hide.

Itis; tobe understood that the; process ofmy inven: tion is not limited tothe situation where; the hair is ultimately'removed from the carcass throughthe use of high pressure jetstreams, although this is my preferred embodiment.- Other dehairing devices can be employed which will operate more efficiently by virtue of the improved loosening of-the hair follicles. The uniformity of. dehairing through the useof my process results in substantial money savings due to the elimination of certain direct-labor charges and the decreased time necessary for the operation.

Another of the features of my invention is that it is possible to carry out the loosening process in equipment much smaller in. size than. the, huge scalding tanks. used inpresent processes. Thus, smaller space requirements for the-operation are possible. Further, with the elimination of complex mechanical dehai'ring machines, a high maintenance cost is also removed.

Referring, now to the drawing, embodiments of apparatusfor carryingoutmy loosening process will be. described in detail. In Figures 1 and 2,, hogs, 1!) proceed. alongthe. bleeding rail 11 to chute, 12 where they slide. into the one. open end of. peripheral chamber 13. of, cylindrical' means 14. Cylindrical means 14 rotates about shaft- 15 driven by motor 16. Each of. the peripheral chambers 13. are fitted withv small longitudinally disposed bars 17 to keep the carcass; raised from, the inner walls of the chamber. The rotation of cylindrical meansll is timedwith the. dropping of hogs down chute 12 and is preferably intermittent to allow time for this. opera.-. tion. The, endof. each of the peripheral chambers facing away from chute. 12 is closed. Thus, itwill be seen that each peripheral chamber 13 opens. longitudinally on, the I 20 which engages, stationary arcuate closure means 21 v upon rotation, to. provide a pressure sealfor. each chamber openingthereundei Extending through arcuate closure. means. 21, arev inlet means. 22, 23- and 2,4, for the admission of steam, air and. water. mist to pressurize each chamber opening thereunder. Theamounts of air, steamand water mist admitted through inlets 22, 23 and 24 will be. predetermine in. ac rd nce with the. conditions of pressure, temperature. and humidity to, which the carcass is, to be. subjected. The admission. can be timed withthe intermittcnt rotation, of cylindrical means 114. Gasket means. 20 can. be. constructed of anysuitable material, such, as bearing. metal, hard rubber, plastic, orthe like, and is tightly secured to cylindrical means. 1.4 so that when engaging the under side of arcuate. closure means 21 a pressure-tight seal is maintained Within the chambers opening thereunder until they reach the end ofthe-closure-means. At that time hog-10 falls out of chamber 13onto chute 24' Where it is picked upand passed to-subsequent -dehairing.

Arcuate closure means 21 is preferably constructed of steel and is shaped so that the open ends and cor-responding longitudinal openings in each of the peripheral chamberswill. be covered. asthe rotation. proceeds. When closure means 21 and cylindrical means 14 are machined to close tolerances, it is possible to eliminate gaskets 20.

Figures 5 and 6 of the drawing illustrate an embodiment of the apparatus in which the hog carcasses may be subjected to the action of high pressure jets of water to remove the hair from thecarcass. Each carcass is picked up and shackled and proceeds along rail which extends through anelongated chamber 31' provided with a plurality of jets 32 which are directed preferably at an angle of about 45 downwardly at each carcass as it proceeds. alongrail 30. Thejets are arranged in such a manner that they are directed atsubstantially the entire surface area of each carcass and the chamber is provided with turning bars 37 and 38 to rotate the carcass as it proceeds. The bottom of chamber 31 may be fitted with a screen 33 to collect the hair and filter it out of the water which proceeds through pipe 34 to chamber 35 for settlingbeforerecirculation by means of-pump 36 to jets 32;

Figures-3 and 4 of-the: drawing illustrate an embodimentsomewhatsimilar to that illustrated in- Figures 1 and 2, except thatthe axis of the rotating cylindrical means is vertically disposed; Other differences are apparent from the drawing;

Hogs 40proceed alongbleeding rail" 41 tocylindrical rotating means 42 which is provided with a plurality of peripheral chambers 43 opening longitudinally on the peripheral surface of cylindrical means 42; Cylindrical means-42 rotates about vertically disposed shaft 43 which is driven by-means'not shown. Disposed lengthwisedown the peripheral surface of cylindrical means 42 are a plurality of gasket means45, securely attached thereto, and arranged to, engage stationaryarcuate closure means 46 which extendsa-lmost completely around cylindrical means 42: The bottom and top of each peripheral chamber 43 is closed and" the edges. extend outwardly to engage clo sure means; 46st) that on rotation any of the peripheral chambers coming thereunder will be entirely closed and; pressure tight. Extending through arcuate closure means 46 are inlet means 50, 5 1. and 52 for the admissionof steam, air and-water mist to each chamber as its opening contacts same. As each of the peripheral chambers 43. is heated; pressurized and moisturized; and the hog con; tained" therein subjectedto the treatment ofthe steam, air and" mist, the cylindricalmeans 42 rotates, and as eachof the chambers reaches the end of arcuate closure means 461, the pressure islost and the-hog carcass is removed. on rail 53 which connects with rail 30, Figures Sand 6, leading intothe; dehairing apparatus. It will be appreciated that the dehairingoperation should take place. as soon as possible after treatment with steam, air and moisture so as to avoid-unnecessary-cooling'ofthe carcass. Each ofthei peripheral chambers 43- is fitted with a rail 54 upon which; the hog-carcass is hung during the treatment in the apparatus. The rotation of theapparatus can be intermittent; so that as onehogisadmitted from rail 41 into. a peripheral chamber 42 another-hog is removed, after having been treated, onto. rail 53; The intermittentoperationcan=be controlled by means of a timing-switch, notshown; sothat each hog will. be subjected to conditions of tem l terature; pressure. and moisture fora period of time suflicient to carry out the process. Further, the admissionof' teamednd mi t. toth chamber-can alsobecontrolled by, meansof the same timingpwitcht While this invention hasbeendescribcd and exemplifiedin terms of, its preferred, modifications, those. skilled in the; art. will. readily appreciate that many modifications. can be, made without departing. from. the spirit and scopeot the n ention.

1. A process for they removal offilamentary keratinousv material from. n. animatv carcass comprising subje t n said carcass to a temperature inth range 0i 1.25 to 50,0? F. and'a total pressure of 20 to pounds per squareinch,

absolute and a partial water vapor pressure of at least 4 pounds per square inch absolute, for a period of at least 5 seconds and subsequently subjecting said carcass to a mechanical dehairing action to remove the loosened filamentary material.

2. A process for the removal of hair from a hog carcass comprising subjecting said carcass to a temperature of from 125 to 500 F. and a total pressure of 20 to 100 pounds per square inch absolute and a partial Water vapor pressure of 4 to about 100 pounds per square inch absolute, for a period of from 5 seconds to 7 minutes and subsequently subjecting said carcass to the action of a high pressure jet stream to remove the loosened hair filaments.

3. In the removal of filamentary keratinous material from an animal carcass, the step of loosening said material prior to removal by subjecting said carcass to a temperature of 125 to 500 F. and a total pressure of 20 to 100 pounds per square inch absolute and a partial water vapor pressure of at least 4 pounds per square inch absolute for a period of at least 5 seconds.

4. In the removal of hair from a hog carcass, the step of loosening said hair prior to actual removal by subjecting said carcass to a temperature of 125 to 500 F. and a total pressure of 20 to 100 pounds per square inch absolute and a partial water vapor pressure of from 4 to about 100 pounds per square inch absolute for a period of from 5 seconds to 7 minutes.

5. In the removal of filamentary keratinous material from an animal carcass, the step of loosening said material prior to removal by subjecting said carcass to a temperature of about 150 to 170 F. for about one half to three minutes with a total pressure of about pounds per square inch absolute having a partial Water vapor pressure of about 15 pounds per square inch absolute.

6. A process for the removal of filamentary keratinous material from an animal carcass comprising subjecting said carcass to a temperature in the range of 125 to 500 F. in a total pressure of 20 to pounds per square inch absolute and a partial water vapor pressure of at least 4 pounds per square inch absolute, for a period of at least 5 seconds and subsequently subjecting said carcass to a hydraulic dehairing action to remove the loosened filamentary material.

References Cited in the file of this patent UNITED STATES PATENTS 1,383,347 Stallman July 5, 1921 2,085,856 McKee et al. June 22, 1937 2,084,857 McKee et al June 22, 1937 2,100,299 Tobin Nov. 23, 1937 

